Vehicle radio antennas are commonly raised and lowered so that during radio or other communications listening the antenna receives signals and whenever the radio or vehicle ignition is turned off, the antenna is lowered into a vehicle fender well. In the prior art, the raising and lowering of the vehicle antenna is typically accomplished by energizing a relay to open and close relay contacts that energize an antenna drive motor.
The prior art relay contacts are susceptible to damage if the relay is rapidly switched on and off. The mechanical switch of the prior art relay can typically safely experience 10 amperes, but rapid switching on and off of the vehicle radio can produce motor surge currents that burn out the relay. The mean time between failures of such prior art relays is much less than manufacturer specifications due to high surge currents caused by rapid switching on and off of the vehicle radio. Rapid switching is a normal condition that is experienced at start-up, but can produce surge currents of up to 25 amperes.